The Network for Integrated Behavioural Science (NIBS) is hosting an interdisciplinary international conference on 'Assessing well-being when preferences are incoherent'. Economists have always been concerned not only with description and prediction, but also with the evaluation of alternative economic policies and institutions. Traditionally there has been a broad consensus in favour of using preference-satisfaction as a principal criterion in such work. However, this approach has been undermined by recent work in cognitive psychology and behavioural economics which shows that individuals?? revealed preferences are often influenced by contextual and framing factors that seem unrelated to well-being. A lot of work has been done to uncover the causal mechanisms behind these effects, and to explore how policy-makers can use these effects to promote specific behaviour changes that are deemed desirable. But behavioural welfare economics, in the sense of general and operational criteria for evaluating alternative policy options when individuals lack coherent preferences, is still a relatively undeveloped research terrain. The problem of developing such criteria is a major research theme of the ESRC Network for Integrated Behavioural Science (NIBS). We believe that a solution to this problem will require the integration of ideas from economics, psychology, public policy analysis, and moral, legal and political philosophy.